In the emerging field of catheter based valve interventions without open heart surgery, localization of the valve plane is important for deployment of artificial heart valves. Inaccurate localization leads to misplacement of the valve and thus potentially causes serious complications such as valve dislodgement, leakage due to lack of an effective seal and obstruction of adjacent vital structures such as coronary arteries. Such complications obviously are not safe for the patient and very often threaten the patient's life.
Current methods of valve plane localization include the use of fluoroscopy whereby the interventionalist obtains fluoroscopic images of the valve region until the optimal orthogonal projections of the valve root are obtained. These projections are then used as frame of reference for proper placement of the replacement valve. An article that describes one such fluoroscopic approach to valve placement is Fluoroscopy-Guided Aortic Root Imaging for TAVR as found in the “Letters to the Editor” section of the JACC: Cardiovascular Imaging, Vol. 6, No. 2, 2013, the entire contents of which is incorporated herein by reference.
Another method of valve plane localization is the use of Computed Tomography (CT) Imaging. The CT images from a patient's valve root are manipulated using software to enable the interventionalist to locate the valve plane and thus use those images for proper placement of the replacement valve. An article that describes one such CT Imaging approach to valve placement is Determination of the Aortic Annulus Plane in CT Imaging—A Step by step Approach, J Am Coll Cardiol Img. 2013; 6(2):275-278, dated Jun. 15, 2012, the entire contents of which is incorporated herein by reference.
There are non-trivial drawbacks, however, to current approaches to valve plane localization. For example, fluoroscopy approaches tend to require the use of significant amounts of contrast medium which, in turn, places a significant burden on the patient's kidneys. Another example is that CT imaging requires the use of a cumbersome and very expensive imager. Hence, there are significant barriers to gaining wide acceptance of CT imaging as a placement tool.
As a result there is a strong need for a device and method that effectively achieves valve plane localization and that is safer for the patient and more readily available to a wide spectrum of interventionalists.